1. Field of Invention
The present invention relates to a 2,2′-bis(dialkylphosphino)biphenyl compound and a production method thereof. The biphenyl compound can be used as a ligand of a metal complex useful as a catalyst for asymmetric synthesis or an anticancer agent. In addition, the present invention also relates to a metal complex comprising the aforementioned biphenyl compound as a ligand.
2. Description of the Related Art
An optically active phosphine ligand having an asymmetric center on a phosphorus atom plays an important role in a catalytic asymmetric synthesis reaction using a transition metal complex. As such optically active phosphine ligand having an asymmetric center on a phosphorus atom, a 1,2-bis(dialkylphosphino)benzene derivative has been proposed in Japanese Patent Laid-Open No. 2000-319288.
Japanese Patent Laid-Open No. 2007-56007 proposes a 2,3-bis(dialkylphosphino)pyrazine derivative. This pyrazine derivative is derived from a pyrazine skeleton, and thus it is characterized in that it has extremely high electron-attracting properties, thereby causing a low electron density of phosphorus atoms at the phosphine site. A metal complex comprising this pyrazine derivative as a ligand is effectively used as a catalyst for reactions, in which the above-mentioned characteristics of the derivative are utilized.
On the other hand, it has been known that a metal complex comprising an optically active phosphine ligand having an asymmetric center on a phosphorus atom is useful, not only as a catalyst for an asymmetric synthesis reaction, but also as an anticancer agent (see International Publication WO 2007/139176, for example).
The present invention provides a phosphine compound capable of forming a metal complex that is more useful than the case of using previously known phosphine ligand, a production method thereof, and a metal complex comprising the phosphine compound as a ligand.